Like Kate, you can also enjoy zero gravity—you only need to pay for it. These kind of flights have been used since 1959 by NASA, back in the time of the Mercury program:

They work by making an airplane to follow a parabolic flight path. The airplane first climbs at 45 degrees, reducing thrust and leveling the plane, then diving down. The sense of zero gravity lasts for about 25 seconds. The airplane makes these parabolas one after the other, like a roller coaster, which eventually causes many people to vomit—hence the nickname for the airplanes used for this kind of training: Vomit Comet.